Dying on downhills (was "Spark or Gas?")

You are doing great. Now check the float level in the carb. Let it idle for a bit, then turn teh engine off, and remove the carb top. 5 screws. Measure gasoline level from the top edge of the float chamber. The bentley book should have the correct value. I dont have my books with me (Here in FL) so I can't tell you what it is.

Keep cleaning the idle jet and the passages behind it. A good blow with a compressor driven air gun would be best.. but an electronics work Bottled air would help too. I know you know what I mean ;)

Jan

Have you got the Bocar carb, or the German made Pierburg? The Bocar has been known to have "issues" even when new, hopefully someone can chime in with a fix...

"Patience my dear" :o)

J.

Neither, maybe. The carb was from aircooled.net. It is a Pierburg. But German made? I don't know: Ronnie of Old Volks in AZ says that he sells them, too, and that these carbs are actually made in China under license from Pierburg.

Always good advice. Will be taking a longish freeway cruise tomorrow down to San Diego. Carb-adjusting screwdriver at the ready.

-- Mike "Rocket J Squirrel" Elliott

Thanks to Braukuche Dan I am now the proud owner of a stock 71 bus air preheat stovepipe. It's getting degunked right now. Next step will be to figure out how it mounts. And what is that asbestos jacket for? The air can't be that hot, since I gather that you use the same paper hose that connects the doghouse to the heater boxes.

Readjusted the carbs yesterday evening. Without a CO monitor (anyone want to loan me one?) and considering the squishiness of the mixture screw, I did the best I could. Idle seems more stable.

Say -- am I overlooking something? Yesterday I plugged the two big inlets on the oil bath air cleaner with my hands and the engine continued to run. The small inlet for the emissions canister is presently plugged and the other small inlet is connected to the crankcase for PCV. Puzzled, I sprayed all around the carb and the rubber carb-to-cleaner boot with carb cleaner and found no sign of a leak. Used my third hand for the spraying since my other two hands were plugging. From where might the carb be getting air? This seems too simple a puzzle to not have been instantly solved. Yet I remain,

Confounded in Carlsbad.

-- Mike "Rocket J Squirrel" Elliott

I think it's more for insulation. To keep that air from cooling off too much.

Max

I s'pose. Maybe in snow country the 6'' of stovepipe below the engine is exposed to significantly colder air than is the 18'' of paper tubing in the engine compartment.

-- Mike "Rocket J Squirrel" Elliott

Yes, new 34 PICT-3 from aircooled.net. No visible spring around mixture screw, the screw is entirely recessed in the carb as is the larger idle screw. Your idea about noting the position of the screw then waiting to see if it shifts is a good one. What I probably need to do is pull the carb and take it a little apart to see if I can find anything odd.

-- Mike "Rocket J Squirrel" Elliott

The o-ring on the head of the mixture screw seals the passage and also provides the friction to keep it from rotating by itself.

RT

That makes sense. I recall that after I installed the carb and started to make the initial adjustments, that a sliver or splinter of black rubber was protruding from the mixture screw access opening, that this sliver of rubber prevented the screwdriver tip from seating into the slot on the screw. I may have received a carb with a damaged o-ring. I wish I had more fully inspected it prior to installation. Oh well.

Check if that o-ring is ok. Replace the screw with the o-ring prelubricated with some WD40 or a drop of engine oil, then wipe it with a cloth. It needs just enough oil so that it slips in the hole without getting damaged. Oil also helps to rotate the adj. screw without binding.

Before adjusting the mixture / volume screws of the carb, make sure you have adjusted the throttle butterfly so that it closses almost fully (if you haven't allready done so). To adjust the throttle butterfly, unscrew the adj screw all the way out, until it doesn't touch the fast idle cam (on the lower step - normal speed idle setting). Then turn it in until it just touches the cam then additional

Bill, '67 bug.

If the problem persists, then you might have to clean the carb. New carbs need cleaning before installation.

Bill, '67 bug.

Thanks, Bill. That adjusting of the throttle adjustment screw procedure is a little bit difficult -- at least I'm having a hard time with it on my carb. For me, when I turn it in, it's difficult to tell when it just contacts the cam. I can't tell by touch, as the cam seems to want to rotate, a moving target. I've put a white piece of paper between the cam and the carb and have looked at the contacting point from the side through a mirror, but that's a bit ambiguous. More practice is probably needed.

You don't have to be that accurate, a close adjustment would be ok. What you want is the thtottle butterfly to be almost completelly closed (when the electric choke is completelly warmed up and the fast idle cam to the lowest position) so that the idle circuit of the carb works properlly. But it must not be all the way closed because the butterfly will bind on the carb's body chewing it bit by bit. To avoid this you have to give a bit of clearance so that the buterflly bottoms on the adjusting screw and not on the carb body.

Bill, '67 bug.

Thanks, Bill.

-- RJS